The invention relates to an open topped drawer, used for transporting live poultry, in which the drawers are held in the drawers are held in racks, the drawers being stored one above the other, to permit the transportation of large numbers of live poultry, and in particular, to such a drawer which is manufactured by injection moulding thermoplastic techniques.
Transportation of live poultry in vehicles and in lift trucks involves the placing of live poultry in open-topped rectangular drawers, and the drawers are then slid into racks on the vehicle for transportation. The drawers must be well ventilated to avoid harm to the live poultry during transportation. In addition, the drawers must be of a substantial size, for economical handling on transportation vehicles. The drawers must be engineered to support large quantities of live poultry, and to be readily adaptable to be cleaned between each usage and to be reused many times over. The drawers must also provide a secure footing for the poultry which may otherwise slide on the floor during transportation, and be injured. At the same time, such drawers should be so constructed that when installed and supported on their racks, they are securely held in position, and cannot easily become displaced during movement.
The handling of loaded poultry drawers is usually carried out by loading vehicles such as fork lift trucks or similar loading vehicles. Usually the transportation vehicle will have a large metal rack framework erected on the vehicle bed, and there will be spaces in the rack framework into which the drawers can be slid one at a time. In most cases, the drawers loaded with live poultry will be lifted one at a time by the fork lift truck operated by a driver who will then swing around and insert the drawer into an appropriate rack on the transportation vehicle.
During this process, the drawers are subjected to various impacts both as a result of an insertion of the forks or tines of the fork lift vehicle underneath the drawers to lift them up, and also as a result of the sliding of the drawers into their racks on the transportation vehicle. The drawers are of substantial size and carry a large number of live poultry. As a result, the total weight of each loaded drawer is considerable. Any impact on the thermoplastic material of which the drawer is made will cause substantial stresses due to the considerable mass of the loaded drawer.
In the past, such thermoplastic drawers as have been available, have been known to experience a variety of problems.
In the first place, the design and manufacture of the floor of the drawer, in the past, has often not been sufficient to withstand the weight of the large numbers of live poultry in the drawer, and as a result, the floor of the drawer tends to sag or bow downwardly in a more or less convex fashion. This downward flexing of the floor both sets up severe fatigue stresses in the plastic and also causes the drawer to be flexed out of shape so that it does not readily slide into its rack. It is well known that most thermoplastics have a relatively low fatigue life, and consequently any excessive fatigue stresses on the plastic will lead to early failure and this has, in fact, happened in the past.
The downward bowing of the floor of one drawer has tended to cause the floor of one drawer to interfere with the racks and even with the side walls of the next drawer beneath it and so on, so that in some cases considerable force has to be exerted on the drawer to force it into its rack and cause it to ride up over the obstruction caused by bowing of the floor.
Further problems have been encountered in the design of the side walls of the drawers. As the drawers are inserted into their racks, there is frequently a certain minor degree of misalignment between the side walls of the drawer and the sides of the rack. As a result, one of the side walls may impact on some portion of the rack frame and again such impacts when repeated over time will cause rapid failure of thermoplastic materials.
Failure or breakage of a drawer may cause large numbers of live poultry to be either lost or simply injured. For example, if the floor bows down then the live poultry will not be supported evenly on the floor of the drawer and will tend to slide down to the lowest point of the floor. This will cause overcrowding of certain areas in each drawer and some live poultry will become injured and as a result making them an unacceptable form. The same thing can happen if the floor is smooth so that the poultry cannot obtain a secure footing.
The cleansing of the drawers which must be carried out between each usage to keep the drawers sterile is an important factor in the design of drawers especially bearing in mind that they are manufactured out of thermoplastic materials. The manufacture of such materials permits the incorporation of numerous openings in the side walls and in the floor of the drawers to provide ventilation but at the same time such openings readily accumulate debris and must be capable of being thoroughly cleansed. In addition to all of these factors, the injection moulding of the drawers in a single piece of thermoplastic material sets up its own list of engineering problems all of which must to be addressed, together with the other problems enumerated above. Storage of drawers between use requires stacking of the drawers, and their design must facilitate this function. Various forms of such drawers and trays are illustrated in earlier patents, details of which are set out in the list of patents relating to this type of product but in spite of significant improvements represented in these earlier patents the actual products still exhibit some of the problems described above.
With a view therefore to providing a drawer having a greater ability to satisfy the foregoing problems, the invention comprises an integral one piece injection moulded drawer suitable for carrying live poultry on a road vehicle, the drawer comprising side walls and end walls formed integrally together and meeting at corners, and a floor formed integrally with the side walls and end walls, and intersecting ribs extend downwardly from the said floor and extending from end to end and side to side of said drawer and defining generally rectangular spaces there between, and a plurality of intersecting bars located within said rectangular spaces, defining together an integral generally honeycomb floor structure, and wherein the floor is shaped with a generally shallow convexly curved dome-like profile, extending upwardly between said side and end walls, and said side walls being formed of intersecting ribs defining generally rectangular spaces there between, and said corners defining generally rounded corner formations.
More particularly the invention provides that the corners are formed of inner and outer radiused corner walls, the outer walls extending from the outer most periphery of the side wall and end wall ribs, and the inner corner walls extending integrally from the inner most edges of the ribs of the side and end walls. The invention further provides that the vertical ribs in the side walls, at spaced intervals, are joined to the transverse ribs in the floor by means of concave junction walls formed integrally therewith.
The invention further provides that the lengthwise ribs in the floor, and the bars at each end of the floor, are merged into integrally formed, generally curved junction walls, providing a curved junction wall between the floor and the end walls.
The invention further provides that the side walls and end walls at their upper extremities are provided with generally continuous side and end wall flanges, located in the generally horizontal plane, and including interior side and end wall reinforcement flanges, extending downwardly from said top wall flanges. The invention further provides that the end wall flanges terminate at a level below said side wall flanges thereby to define respective end wall notches at either end of said drawer.
The various features of novelty which characterize the invention are pointed out with more particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.